This invention relates generally to indexing and positioning devices and more particularly to an indexing and positioning device capable of readily indexing the angle of revolution of a workpiece set on a turntable which is revolvable about an axis of revolution.
In general, indexing devices are widely used where the outer circular peripheries of articles are divided evenly or where a specific rotational angle is imparted to an article from a datum position. Among indexing devices of this character known in the prior art, those combining a geneva gear and a pin and those combining a ratchet wheel and a pawl have been used. While these indexing devices are of relatively simple construction, they have had the drawback of a lowered indexing precision due to an increasing back-lash and gaps caused by abrasive wear of parts such as main shafts and pins.
Furthermore, indexing devices in which crown gears are used are also being employed. This type of indexing device has the advantage of high precision, but has been accompanied by the problems of high price, a tendency to be bulky, and a difficulty in making it compact.